chore: add plugin selection and fix encoding in gRPC example

examples/bidirectional/.gitignore

@@ -0,0 +1,3 @@
+/counter
+/counter-*
+/kv_*

examples/bidirectional/shared/grpc.go

@@ -77,7 +77,7 @@ func (m *GRPCServer) Get(ctx context.Context, req *proto.GetRequest) (*proto.Get
 	return &proto.GetResponse{Value: v}, err
 }
 
-// GRPCClient is an implementation of KV that talks over RPC.
+// GRPCAddHelperClient is an implementation of AddHelper that talks over RPC.
 type GRPCAddHelperClient struct{ client proto.AddHelperClient }
 
 func (m *GRPCAddHelperClient) Sum(a, b int64) (int64, error) {
@@ -92,7 +92,7 @@ func (m *GRPCAddHelperClient) Sum(a, b int64) (int64, error) {
 	return resp.R, err
 }
 
-// Here is the gRPC server that GRPCClient talks to.
+// Here is the gRPC server that GRPCAddHelperClient talks to.
 type GRPCAddHelperServer struct {
 	// This is the real implementation
 	Impl AddHelper

examples/bidirectional/shared/interface.go

@@ -29,7 +29,7 @@ type AddHelper interface {
 	Sum(int64, int64) (int64, error)
 }
 
-// KV is the interface that we're exposing as a plugin.
+// Counter is the interface that we're exposing as a plugin.
 type Counter interface {
 	Put(key string, value int64, a AddHelper) error
 	Get(key string) (int64, error)

examples/grpc/README.md

@@ -10,7 +10,8 @@ $ go build -o kv
 # This builds the plugin written in Go
 $ go build -o kv-go-grpc ./plugin-go-grpc
 
-# This tells the KV binary to use the "kv-go-grpc" binary
+# This tells the KV binary to use the "kv-go-grpc" binary over gRPC
+$ export KV_PLUGIN_NAME=kv_grpc
 $ export KV_PLUGIN="./kv-go-grpc"
 
 # Read and write
@@ -24,34 +25,37 @@ world
 
 This plugin uses gRPC to serve a plugin that is written in Go:
 
-```
+```sh
 # This builds the plugin written in Go
 $ go build -o kv-go-grpc ./plugin-go-grpc
 
-# This tells the KV binary to use the "kv-go-grpc" binary
+# This tells the KV binary to use the "kv-go-grpc" binary over gRPC
+$ export KV_PLUGIN_NAME=kv_grpc
 $ export KV_PLUGIN="./kv-go-grpc"
 ```
 
 ### Plugin: plugin-go-netrpc
 
 This plugin uses the builtin Go net/rpc mechanism to serve the plugin:
 
-```
+```sh
 # This builds the plugin written in Go
 $ go build -o kv-go-netrpc ./plugin-go-netrpc
 
-# This tells the KV binary to use the "kv-go-netrpc" binary
+# This tells the KV binary to use the "kv-go-netrpc" binary over net/rpc
+$ export KV_PLUGIN_NAME=kv
 $ export KV_PLUGIN="./kv-go-netrpc"
 ```
 
 ### Plugin: plugin-python
 
 This plugin is written in Python:
 
-```
+```sh
 $ python -m venv plugin-python/.venv
 $ source plugin-python/.venv/bin/activate
 $ pip install -r plugin-python/requirements.txt
+$ export KV_PLUGIN_NAME=kv_grpc
 $ export KV_PLUGIN="python plugin-python/plugin.py"
 ```
 

examples/grpc/main.go

@@ -31,8 +31,19 @@ func run() error {
 		return err
 	}
 
+	var pluginName string
+	switch os.Getenv("KV_PROTO") {
+	case "netrpc":
+		pluginName = shared.PluginNetRPC
+	case "grpc":
+		pluginName = shared.PluginGRPC
+	default:
+		fmt.Println("must set KV_PROTO to netrpc or grpc")
+		os.Exit(1)
+	}
+
 	// Request the plugin
-	raw, err := rpcClient.Dispense("kv_grpc")
+	raw, err := rpcClient.Dispense(pluginName)
 	if err != nil {
 		return err
 	}

examples/grpc/plugin-python/plugin.py

@@ -25,7 +25,7 @@ def Get(self, request, context):
 
     def Put(self, request, context):
         filename = "kv_"+request.key
-        value = "{0}\n\nWritten from plugin-python".format(request.value)
+        value = "{0}\n\nWritten from plugin-python".format(request.value.decode('utf-8'))
         with open(filename, 'w') as f:
             f.write(value)
 

examples/grpc/shared/interface.go

@@ -14,6 +14,11 @@ import (
 	"github.com/hashicorp/go-plugin/examples/grpc/proto"
 )
 
+const (
+	PluginNetRPC = "kv"
+	PluginGRPC   = "kv_grpc"
+)
+
 // Handshake is a common handshake that is shared by plugin and host.
 var Handshake = plugin.HandshakeConfig{
 	// This isn't required when using VersionedPlugins
@@ -24,8 +29,8 @@ var Handshake = plugin.HandshakeConfig{
 
 // PluginMap is the map of plugins we can dispense.
 var PluginMap = map[string]plugin.Plugin{
-	"kv_grpc": &KVGRPCPlugin{},
-	"kv":      &KVPlugin{},
+	PluginGRPC:   &KVGRPCPlugin{},
+	PluginNetRPC: &KVPlugin{},
 }
 
 // KV is the interface that we're exposing as a plugin.